In a searing speech outside Downing Street, she pledged to "fight against the burning injustices" surrounding poverty, race, class and health and to give people back "control" of their lives.

It marked a significant break with David Cameron's government with its focus on austerity and the "long-term economic plan".

With her husband, Philip, standing behind her, Ms May said that she wanted people "to go as far as your talents will take you" as she vowed to "prioritise" tax cuts and legislation for working-class voters rather than the "mighty".

Her speech, setting out her vision as a 'One Nation' Conservative, marked a clear attempt to distance herself from Mr Cameron's premiership and to appeal directly to disenchanted Labour voters.

She said that for an "ordinary working-class family" life was "much harder than many people in Westminster realise" as she sought to heal the national divide after the EU referendum.

Her speech highlighted her clear intention to reach out to Labour voters who feel alienated by Jeremy Corbyn, in a move which could put the Tories in power for a decade.

After arriving in Downing Street, she said that her "mission" as prime minister would be to make Britain "a country that works for everyone".

She also vowed to "forge a bold new positive role" for Britain outside the European Union.

Mrs May indicated that she was preparing to unveil a series of policies to improve life chances, tackle the cost of living and give people greater job security as part of her pledge to "build a better Britain".

The new prime minister said: "From the introduction of same-sex marriage to taking people on low wages out of income tax altogether, David Cameron has led a One Nation government and it is in that spirit that I also plan to lead."

She added: "As we leave the European Union, we will forge a bold new positive role for ourselves in the world and we will make Britain a country that works not for a privileged few but for every one of us.

"That will be the mission of the government I lead and together we will build a better Britain."

Ms May gave her speech after being formally appointed by Queen Elizabeth during her first private audience.